Battery systems in motor vehicles are generally operated in a certain temperature range in order to achieve highly optimal performance and service life. A wide variety of temperature control systems are known that can be used to guarantee said objective. Mostly, a cooling circuit with a liquid or gaseous coolant is used in order to heat or cool the battery system as required and thus to keep within the desired temperature range. Such cooling circuits for the temperature control of a battery system generally comprise a plurality of heating and/or cooling components, such as e.g. an air conditioning system and a low temperature cooling device with a fan. A variety of configurations is now conceivable, in which said heating and/or cooling elements are disposed in the cooling circuit and can be operated continuously or discretely, mixed, additionally or alternatively to each other in order to bring the coolant in the cooling circuit to a desired temperature in order to keep the battery system within the desired temperature range.
With all said configurations it is common that this is achieved by different, continuously and/or discretely operated controllers for the individual heating and/or cooling elements, which can be connected in suitable combinations with each other. Said suitable combinations can cause the battery system to be heated or cooled accordingly depending on different boundary conditions.
In certain systems, the controllers for the individual heating and/or cooling elements of the cooling circuit are switched depending on the boundary conditions and the temperature in the battery system. If the desired battery temperature is not achieved, then a fault is signaled. In this it is necessary to adapt the logic that switches the controllers depending on the configuration of the cooling circuit in a complex manner; the logic is complex and unclear for the application.